Detection and impact estimation of social bots in the Chilean Twitter network.

The rise of bots that mimic human behavior represents one of the most pressing threats to healthy information environments on social media. Many bots are designed to increase the visibility of low-quality content, spread misinformation, and artificially boost the reach of brands and politicians. These bots can also disrupt civic action coordination, such as by flooding a hashtag with spam and undermining political mobilization. Social media platforms have recognized these malicious bots' risks and implemented strict policies and protocols to block automated accounts. However, effective bot detection methods for Spanish are still in their early stages. Many studies and tools used for Spanish are based on English-language models and lack performance evaluations in Spanish. In response to this need, we have developed a method for detecting bots in Spanish called Botcheck. Botcheck was trained on a collection of Spanish-language accounts annotated in Twibot-20, a large-scale dataset featuring thousands of accounts annotated by humans in various languages. We evaluated Botcheck's performance on a large set of labeled accounts and found that it outperforms other competitive methods, including deep learning-based methods. As a case study, we used Botcheck to analyze the 2021 Chilean Presidential elections and discovered evidence of bot account intervention during the electoral term. In addition, we conducted an external validation of the accounts detected by Botcheck in the case study and found our method to be highly effective. We have also observed differences in behavior among the bots that are following the social media accounts of official presidential candidates.

The cardiovascular polypill as baseline treatment improves lipid profile and blood pressure regardless of body mass index in patients with cardiovascular disease. The Bacus study.

BACKGROUND: Pharmacological treatment with lipid-lowering and antihypertensive drugs has been proposed as a strategy to improve excess cardiovascular (CV) risk among obese individuals. The present study aimed to assess whether the CV polypill (Sincronium®) could be an effective strategy to help improve CV risk factor control in obese/overweight individuals requiring secondary prevention. METHODS: This was an observational, retrospective study reviewing the hospital medical records of 479 patients with established CV disease who initiated treatment with the CV polypill between 2013 and 2019 at a general hospital in Mexico. Patients were grouped as normal weight, overweight or obese according to their initial body mass index (BMI). We collected blood pressure (BP), lipid profile, and vascular age at the last visit recorded during the period following treatment. RESULTS: At the end of the study, all assessed lipid parameters improved compared to baseline regardless of the initial BMI category (all p<0.001). There was an increase from baseline regarding the proportion of patients with at target low-density lipoprotein cholesterol after treatment (2.3% vs. 30.1%; p<0.001), more than 80% of patients achieved triglyceride levels <200 mg/dL (p<0.001), and more than 80% achieved target BP levels in all BMI subgroups (p<0.001). The subanalyses in the elderly population yielded similar results, with a significant overall improvement in lipid and BP control after initiating the CV polypill strategy. CONCLUSIONS: The use of the CV polypill as baseline therapy for secondary prevention seems to be a reasonable strategy that enhances CV risk factor control regardless of the patient's BMI.

Predicting affinity ties in a surname network.

From administrative registers of last names in Santiago, Chile, we create a surname affinity network that encodes socioeconomic data. This network is a multi-relational graph with nodes representing surnames and edges representing the prevalence of interactions between surnames by socioeconomic decile. We model the prediction of links as a knowledge base completion problem, and find that sharing neighbors is highly predictive of the formation of new links. Importantly, We distinguish between grounded neighbors and neighbors in the embedding space, and find that the latter is more predictive of tie formation. The paper discusses the implications of this finding in explaining the high levels of elite endogamy in Santiago.

Content-Based Medical Image Retrieval and Intelligent Interactive Visual Browser for Medical Education, Research and Care.

Medical imaging is essential nowadays throughout medical education, research, and care. Accordingly, international efforts have been made to set large-scale image repositories for these purposes. Yet, to date, browsing of large-scale medical image repositories has been troublesome, time-consuming, and generally limited by text search engines. A paradigm shift, by means of a query-by-example search engine, would alleviate these constraints and beneficially impact several practical demands throughout the medical field. The current project aims to address this gap in medical imaging consumption by developing a content-based image retrieval (CBIR) system, which combines two image processing architectures based on deep learning. Furthermore, a first-of-its-kind intelligent visual browser was designed that interactively displays a set of imaging examinations with similar visual content on a similarity map, making it possible to search for and efficiently navigate through a large-scale medical imaging repository, even if it has been set with incomplete and curated metadata. Users may, likewise, provide text keywords, in which case the system performs a content- and metadata-based search. The system was fashioned with an anonymizer service and designed to be fully interoperable according to international standards, to stimulate its integration within electronic healthcare systems and its adoption for medical education, research and care. Professionals of the healthcare sector, by means of a self-administered questionnaire, underscored that this CBIR system and intelligent interactive visual browser would be highly useful for these purposes. Further studies are warranted to complete a comprehensive assessment of the performance of the system through case description and protocolized evaluations by medical imaging specialists.

Surname affinity in Santiago, Chile: A network-based approach that uncovers urban segregation.

Based on a geocoded registry of more than four million residents of Santiago, Chile, we build two surname-based networks that reveal the city's population structure. The first network is formed from paternal and maternal surname pairs. The second network is formed from the isonymic distances between the city's neighborhoods. These networks uncover the city's main ethnic groups and their spatial distribution. We match the networks to a socioeconomic index, and find that surnames of high socioeconomic status tend to cluster, be more diverse, and occupy a well-defined quarter of the city. The results are suggestive of a high degree of urban segregation in Santiago.

Effect of Oral Nutritional Supplementation With and Without Exercise on Nutritional Status and Physical Function of Adult Hemodialysis Patients: A Parallel Controlled Clinical Trial (AVANTE-HEMO Study).

OBJECTIVE: Protein energy wasting affects the nutritional status (NS) and physical function (PF) of dialysis patients. Among the different anabolic strategies to improve NS and PF, oral nutritional supplementation (ONS) and resistance exercise (RE) or aerobic exercise (AE) have been shown to be effective. Nevertheless, the combination of both anabolic strategies has not been completely evaluated. The aim of this study is to assess the effect of exercise combined with ONS versus ONS without exercise during hemodialysis sessions on PF and NS indicators. METHODS: Young hemodialysis patients (29 ± 9.3 years) with predominantly unknown causes of renal disease (80%) were divided into the following 3 groups during a period of 12 weeks: (1) ONS (n = 15), (2) ONS + RE (n = 15), and (3) ONS + AE (n = 15). Anthropometric, biochemical, PF, and quality of life measurements were recorded at baseline and after 3 months. Repeated measures analysis of variance and effect sizes (Cohen's d) were used to assess the effect of exercise and nutrition (ISRCTN registry 10251828). RESULTS: At the completion of the study, the ONS and ONS + RE groups exhibited statistically significant increases in body weight, body mass index, and in the percentage of fat mass (P < .05); the greatest effect sizes were observed in the ONS + RE group (d = 0.30 for body weight, d = 0.63 for body mass index, and d = 0.90 for the percentage of fat mass). Groups with RE and AE had statistically significant increases and large effect sizes in the six-minute walk test (RE: d = 0.94, P = .02; AE: d = 1.11, P = .03), sit-to-stand test (RE: d = 0.81, P = .041; AE: d = 1.20, P = .002), timed up and go test (RE: d = 1.04, P = .036; AE: d = 1.6, P = .000), and muscle strength (RE: d = 1.01, P = .000; AE: d = 0.60, P = .003). Regarding quality of life, the ONS + RE group had more areas of improvement at the end of the study, followed by the ONS + AE group. No statistically significant differences were found in the repeated measures ANOVA. CONCLUSIONS: The combination of exercise with ONS had larger effects on PF than on ONS alone. Further studies to examine the impact of exercise on the effect of oral nutritional supplementation in dialysis patients are indicated.